Preparation of brominated indanes

Abstract

A two step bromination process for manufacturing a polybrominated indane product such as octabromophenyl indane comprises the steps of: (a) forming an intermediate by reacting an indane compound with bromine, under reaction conditions so as to dissolve and partially ar-brominate the indane compound to contain an average of at least about two ar-bromine atoms per molecule, and (b) catalytically ar-brominating the intermediate to obtain a polybrominated indane product, the catalytic ar-bromination occurring in the presence of an aluminum or iron containing bromination catalyst or other bromination catalyst having a catalytic activity substantially equivalent thereto and in a mole ratio of bromine to said intermediate of at least 5.

What is claimed is: 
     
       1. A process for the manufacture of a polybrominated indane product, said process comprising the steps of: (a) forming an intermediate by reacting an indane compound with bromine, under reaction conditions so as to dissolve and partially ar-brominate the indane compound to contain an average of at least about two ar-bromine atoms per molecule, the reaction occurring in the presence of from about 0.001 to about 0.1 gram per gram of indane compound of a weak Lewis acid catalyst selected from the group consisting of antimony chlorides, tin chloride, zinc chloride, bismuth chloride, and cadmium chloride or of from about 0.001 to about 0.005 gram per gram of indane compound of a strong Lewis acid catalyst selected from the group consisting of iron containing bromination catalyst, an aluminum containing bromination catalyst, and zirconium tetrachloride bromination catalyst; and   (b) catalytically ar-brominating the intermediate to obtain a polybrominated indane product, the catalytic ar-bromination occurring in the presence of aluminum containing bromination catalyst or iron containing bromination catalyst or zirconium tetrachloride bromination catalyst and in a mole ratio of bromine to said intermediate of at least 5.   
     
     
       2. A process for the manufacture of a polybrominated phenyl indane product, said process comprising the steps of: (a) forming an intermediate by reacting a phenyl indane compound with bromine, under reaction conditions so as to partially ar-brominate the phenyl indane to contain an average of at least about two to about four ar-bromine atoms per molecule, the reaction occurring without the presence of a catalytic amount of a bromination catalyst; and   (b) catalytically ar-brominating the intermediate to obtain a polybrominated phenyl indane product, containing an average of at least about seven ar-bromine atoms per molecule, the catalytic bromination occurring in the presence of aluminum containing bromination catalyst or iron containing bromination catalyst or zirconium tetrachloride bromination catalyst and in a mole ratio of bromine to said intermediate of at least 5.   
     
     
       3. The process according to claim 2 wherein additional bromine is added in step (b). 
     
     
       4. The process according to claim 3 wherein the molar ratio of total bromine present in the process to phenyl indane compound is at least about 14. 
     
     
       5. The process according to claim 4 wherein said molar ratio is from about 14 to 30. 
     
     
       6. The process according to claim 2 wherein said bromination catalyst is a Lewis acid. 
     
     
       7. The process according to claim 6 wherein said catalyst is selected from the group consisting of halides of iron, aluminum, and zirconium. 
     
     
       8. The process according to claim 2 wherein said phenyl indane is 1,3,3-trimethyl-1-phenyl indane and said polybrominated phenyl indane product is predominantly octabromo-1,3,3-trimethyl-1-phenyl indane. 
     
     
       9. The process according to claim 2 wherein said phenyl indane is 1-methyl-3-phenyl indane and said product is predominately octabromo-1-methyl-3-phenyl indane. 
     
     
       10. The process according to claim 2 wherein bromination catalyst system is present in step (a). 
     
     
       11. The process according to claim 2 wherein in step (b) the reaction mixture from step (a) is added to a mixture of bromine and catalyst and the resulting reaction mixture is refluxed so as to produce a polybrominated phenyl indane product which contains an average of at least about 7.5 bromine atoms per molecule of phenyl indane.